1) Field
Embodiments of the present invention pertain to the field of group III-nitride materials and, in particular, to the fabrication of gallium nitride-based optoelectronic or electronic devices with physical vapor deposition (PVD) formed aluminum nitride buffer layers.
2) Description of Related Art
Group III-V materials are playing an ever increasing role in the semiconductor and related, e.g. light-emitting diode (LED), industries. Often, group III-V materials are difficult to grow or deposit on foreign substrates (known as heteroepitaxy) without the formation of defects or cracks. For example, high quality surface preservation of select films, e.g. a gallium nitride film, is not straightforward in many applications using stacks of material layers fabricated sequentially. The inclusion of one or more buffer layers between a substrate and a device layer has been one approach. However, group III-V materials are often sensitive to process conditions and care must be taken to avoid such conditions at particular periods of the fabrication process. Avoiding interaction of a sensitive group III-V film with potential damaging conditions, however, is also not straightforward in many applications.